TEMPERATURES are soaring in Beverly Hills but step inside the Four Seasons hotel suite where Michelle Pfeiffer is waiting and you'd never know it.

Michelle Pfeiffer attributes her youthful looks to love, family and diet tips from Bill Clinton

"Are they trying to keep me awake in here?" she quips, putting on a pashmina to ward off the chill from the air conditioning.

In a black Armani trouser suit, Michelle looks every inch the elegant A-lister as she sips her tea. But in truth she couldn't care less about labels and glamour, and has to ask her publicist "whom" she is wearing.

"People think I lead this glamorous life, but I really don't," she laughs, shaking her head. "I'm just an ordinary mum who happens to be in the movies."

Michelle comes across as fairly reserved in conversation, but she insists that's the polar opposite of how her children see her.

"I talk a lot at home," she says."I try to be very open with my kids. They're like, 'Ahh God.' They wish I'd shut up!

"I love being a parent," she adds with a smile. "There is nothing more rewarding. But it's been the most challenging role I've played.

"I put a lot of pressure on myself to do a great job in a movie, but at a certain point it's just a movie.

"You can't say that when you're rearing a child - it's a life. You never stop being a parent - you're going to worry about them until the day you die."

Still an extraordinary beauty, Michelle recently turned 54 but she could still pass for late 30s. Her skin is flawless - something she puts down to a strict diet.

Watching the US TV documentary The Last Heart Attack - in which former President Bill Clinton reveals that a blocked artery proved the catalyst for him to become vegan - Michelle was inspired to do the same.

"I remember watching that programme thinking, 'Clinton is a smart man and there's true science behind this theory,'" she recalls. "So I cut out meats and dairy. After two months, my cholesterol shot down 83 points. That's enough proof to me that it works."

Michelle admits she had some unhealthy eating habits in her younger years. "I was terrible," she says. "I existed on cigarettes, Coca-Cola and coffee, and I got away with that for a while. And I never used to exercise. I think you begin to look and feel lousy the older you become, so now I eat really well. I don't smoke and I'm learning meditation."

Even so, Michelle admits that there's still an ageist attitude in Hollywood, with good roles sparse for any woman over 40. "An actress's window of opportunity is smaller than an actor's," she says. "You can be the sexiest man alive at 60, but it's not like that if you're a woman. It's just one of those things. Deal with it."

Pfeiffer's big break came when she starred in Grease 2

You can be the sexiest man alive at 60, but it's not like that if you're a woman. It's just one of those things. Deal with it.

Michelle Pfeiffer

Michelle has lived in the limellight for 30-odd years but, somehow, her personal life has remained just that. She celebrates 20 years of marriage this November to 56-year-old writer/producer David E Kelley, who masterminded shows such as LA Law, The Practice and Ally McBeal.

"I do think I've become more relaxed as I've grown older," says Michelle, who has been famously protective of her family in the past.

"I'm not sure why we were never written about and I'm grateful for it. Perhaps it's because people think we're boring. Well, we are!"

Wind the clock back 20 years and Michelle was single after a seven-year marriage to actor Peter Horton.

But, at 34, she desperately wanted to start a family of her own. Rather than wasting time on dating the wrong men, she adopted a daughter, Claudia Rose, now 19.

But her love life took a happy turn that same year when she was set up with David on a blind date by a mutual friend. Michelle insists that he fell in love with Claudia Rose before he fell for her. Be that as it may, within a year the couple were married and Michelle was pregnant with their son, John Henry, now 18.

Today, the actress values her family life in San Francisco over her Hollywood career, and she's more than happy with her lot.

"Life is made up of the choices and I've not always made good choices but I know I picked the right man," she says. "David and I work because we are really compatible. We have similar morals and we both love to balance work and family in the same way. We respect each other, which is really important."

The second of four children, Michelle is a true California girl. Her father Richard was an air-conditioning contractor and her mother Donna was a housewife.

As a teenager, oblivious to her beauty, she considered herself a total tomboy. "I was a surfer girl," she says. "I would sometimes skip school to hang out with the boys down on the beach."

But in 1978, much to Michelle's surprise, her hairdresser gave her an application to enter the Miss Orange County beauty contest. She did, and as well as winning, she was spotted by an agent. Within a year she had landed her first television role in the series Fantasy Island.

To make ends meet she worked as a local supermarket cashier, but her big break came four years later when she won the lead role in Grease 2.

The film received poor reviews but Michelle shone in the role of Stephanie and, with her stunning looks, she could doubtless have had her pick of starring roles. But she held out for character-driven parts, and her patience was rewarded with a role as Al Pacino's wife in the drug-pushing drama Scarface in 1983.

Michelle went on to receive three Oscar nominations - for The Fabulous Baker Boys, Love Field and Dangerous Liaisons, for which she also won a BAFTA - and continued to build on her A-list reputation with starring roles in Batman Returns, One Fine Day and Hairspray.

More recently there was New Year's Eve, in which she enjoyed an on-screen romance with Zac Efron - a heartthrob nearly 30 years her junior.

Pfeiffer alongside Al Pacino in Scarface

She will be back on our screens later this year, working alongside Robert De Niro in the Mafia movie Malavita, but in the meantime it's her role in People Like Us that she's keenest to talk about.

The film is based on director and writer Alex Kurtzman's own experiences and stars Chris Pine (Star Trek) as a twenty-something, fast-talking salesman whose latest business deal collapses on the day he learns that his father has died and he must return home to reconnect with his estranged family.

Michelle, who plays his mourning mother, says she could relate to the film's central theme of family secrets. In the course of fulfilling his father's last wishes, her character's son uncovers a startling revelation - he has an older sister whom he never knew about. And as this new relationship develops, he is forced to re-examine his own life choices.

"My character knows about her husband's love child, but it all happened so long ago that she kind of forgets about it," says Michelle. "And I related to that because I completely forget that I was married before I met my husband. My kids were quite old when I realised I hadn't told them," she explains.

"I thought: 'Ah man, I should probably tell them, because they're going to find out and that's going to be awkward.'

So one day, I just blurted out, 'Oh, by the way, I was married before.' And they were like, 'What?!'"

Pfeiffer with husband David E Kelley: "I know I picked the right man."

Michelle's character - Lillian - is not the most glamorous she has played, but the actress claims not to care. "It can be quite liberating not to have to look your best," she says, "even if it's hard to watch on the big screen."

But then Michelle Pfeiffer can hardly bear to watch herself at all, even at her best. "I will leave the room if one of my films is playing," she winces. "I can't switch the channel fast enough. I'm very critical of my own work so I'm better off not watching it. And now the whole high-definition thing - I just want to kill myself!

"Who wants to see all those lines on their face? Not me. I don't want to see anyone in HD."

And how do her children feel about watching their mum in the movies? "They're not even interested," she says with a smile. "Recently we were channel surfing and Married to the Mob came on. It's been such a long time since I made the film that I now have some distance. I thought, 'They're older now - they can watch it.'

"I actually thought they might like this movie, because it's kinda hip and I don't have any sex scenes in it. We lasted about 20 minutes. They got so bored that I turned the channel to a gardening show."